Free Online Calculators
Small calculators for questions that come up every week: what 20% of a number is and what percentage one number is of another, how many days until a date or between two dates, exactly how old someone is, what a Unix timestamp means in your time zone, a colour in HEX, RGB and HSL, and whether a sofa or a fridge fits through a doorway or round a corner.
Each one works as you type, with no button to press and no page to reload, and reads numbers the way your device writes them, thousands separators included. Nothing you enter is sent anywhere.
The 6 tools
- Unix timestamp converter Convert Unix timestamps in seconds, milliseconds or nanoseconds to dates in any time zone, and dates back, one or a list at once.
- Color converter Convert colors between HEX, RGB, HSL, OKLCH and CMYK, see their shades, tints and harmonies, and check WCAG contrast against white, black or any color.
- Percentage calculator Work out X% of a number, what percent one number is of another, the whole from a part, the percentage change, or a price with or before tax or a discount.
- Age calculator Work out an exact age from a date of birth: years, months and days, the same in weeks and days, the weekday of birth, and how long until the next birthday.
- Date calculator Count the days, weeks, months and working days between two dates, or add or take away days, weeks, months, years or working days from a date.
- Will it fit? Check if a sofa or any furniture fits through a doorway, round a hallway corner or into a lift or car, and which way to tilt it.